Lighting apparatus

ABSTRACT

Lighting apparatus is provided comprising a light source ( 10 ), the light source being encapsulated in a protective medium ( 11 ) to seal the light source against ingress of moisture, the lighting apparatus having a heat sink ( 12, 13 ), the heat sink having a first region ( 12 ) in communication with light source ( 10 ) to receive heat from the light source ( 10 ) and a second region ( 13 ) which projects externally of the protective medium, such that the heat sink can dissipate heat to the ambient area. The invention provides light apparatus which is particularly suitable for use with caving lamps, although other uses are possible, for example in traffic lights or the lights of a motor vehicle, where the encapsulation would provide protection against rain.

The invention relates to lighting apparatus comprising a light source,and particularly though not exclusively, to lighting apparatus for usein a damp or wet environment, for example when caving.

The invention provides lighting apparatus comprising a light source, thelight source being encapsulated in a protective medium to seal the lightsource against ingress of moisture, the lighting apparatus including aheat sink, the heat sink having a first region in communication with thelight source to receive heat from the light source, and a second regionwhich projects externally of the protective medium, such that the heatsink can dissipate heat to the ambient area.

The light source may comprise a light emitting diode (LED).

The light source may have a light emitting region adjacent to, orprojecting from, the protective medium.

Alternatively the light source may have a light emitting regionprotected by a cover, the cover being sealed to the protective mediumand being such that light may pass through it.

The cover may be made of glass.

Alternatively the cover may be made of transparent or translucentplastics material.

The cover may comprise a collimating lens.

There may be more than one light source arranged within the protectivemedium.

The light source may be arranged to transmit light to the ambient areavia a light transmitting conduit such as a light pipe or fibre opticbundle.

The heat sink may comprise a metal plate.

A preferred metal is aluminium and the aluminium may be anodised.

However other metals would be possible, for example copper.

The second region of the heat sink may serve more than one purpose.

It may for example carry manufacturer's information or advertisinglogos.

The second region of the heat sink could be shaped into a bracket, forexample to fit into a socket on a standard miner's or caver's helmet.

The second region of the heat sink may be shaped to form a box or otherenclosure.

While the light apparatus according to the invention has beenparticularly developed for use with caving lamps, other uses arepossible, for example in traffic lights or the lights of a motorvehicle, where the encapsulation would provide protection against rain.

The second region of the heat sink may have a secondary function as partof a car body part such as a car wing.

By way of example specific embodiments of the invention will now bedescribed, with reference to the accompanying drawings, in which:

FIG. 1 is a side cross sectional view through a first embodiment oflighting apparatus according to the invention; and

FIGS. 2 to 7 are similar views of six other embodiments of theinvention.

In the embodiment shown in FIG. 1, an LED 10 has polyurethane 11 mouldedaround it to form a solid block, encapsulating the LED.

The LED 10 is mounted on a heat sink in the form of an anodisedaluminium plate having a first region 12 which is sealed within theblock 11. The heat sink has a second region 13 which extends outside theblock to enable the heat sink to dissipate heat to the ambient area.

A light emitting region 14 of the LED projects slightly from the block11 to enable light to be transmitted by the lighting apparatus. Sincehowever the polyurethane material completely surrounds the LED, there isno possibility of moisture reaching the electrical components of theLED.

The polyurethane material is substantially incompressible and as thereare no hollows or voids within the lighting apparatus, it is immenselystrong and resistant to shocks.

The LED may be switched on and off from outside the apparatus, forexample magnetically using a reed switch or Hall effect transistor.

The LED may also be provided with a dimming device which can also beoperated externally of the device, for example magnetically.

In the alternative embodiment shown in FIG. 2 the LED 10 is protected bya glass cover 15 which is sealed to the encapsulation material 11 bymeans of sealant resin 16.

A further embodiment is shown in FIG. 3 in which the LED 10 is protectedby a transparent plastic cover 17 embedded within the encapsulationmaterial 11.

FIG. 4 illustrates how the external part 13 of the heat sink may begiven a secondary purpose. In the embodiment shown in FIG. 4, theportion 13 is bent into the shape of a bracket so that the lightingapparatus can easily be clipped onto a standard miner's or caver'shelmet.

In the embodiment shown in FIG. 5, the LED 10 lies well within theencapsulation material 11, but light is transmitted to the outside ofthe encapsulation material 11 by means of a light pipe or fibre opticbundle 18.

FIG. 6 illustrates yet another embodiment in which two LEDs 10 arearranged spaced apart within the encapsulating medium 11. The lightemitting portions of the LEDs are protected by a cover 19, for examplemade of polycarbonate, sealed to the polyurethane 11. The heat sink maybe shaped as shown in FIG. 6 to form a box of other enclosure. This formof light apparatus could, for example, be used as a vandal resistantluminaire, or for traffic lights, or for lighting for a motor vehicle.The exposed portions of the heat sink could for example form a car bodypart, such as a car wing.

FIG. 7 illustrates one more embodiment which is similar to that shown inFIG. 6 but in which the exposed, heat dissipating portion 13 of the heatsink comprises only the rear face of the heat sink, the edges 20 of theheat sink being enclosed within the polyurethane 11.

Each of the embodiments shown in the drawings may be provided witheither an external or an internal power supply.

For example, as illustrated in FIG. 1, a power supply for the LED 14 maybe an external power supply, fed to the LED 14 through the encapsulationmaterial 11 by a power cable 21.

Alternatively, as shown in FIG. 5, power cells 22 may be embedded withinthe encapsulation material 11. The cells may be primary cells orsecondary, rechargeable cells.

Although the lighting apparatus has been specifically developed for usewith caving lamps, the apparatus according to the invention also makesan excellent apparatus for safe use in flammable atmospheres. Such lightsources are generally referred to as being “intrinsically safe”. Lightapparatus according to the invention would be intrinsically safe becausethe light source is so well sealed from the environment and the heatsink can be sized so that operating temperatures are well below thoserequired by safety or legislative requirements.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

All of the features disclosed in this specification (including anyaccompanying claims, abstract and drawings), and/or all of the steps ofany method or process so disclosed, may be combined in any combination,except combinations where at least some of such features and/or stepsare mutually exclusive.

Each feature disclosed in this specification (including any accompanyingclaims, abstract and drawings), may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

The invention is not restricted to the details of the foregoingembodiment(s). The invention extends to any novel one, or any novelcombination, of the features disclosed in this specification (includingany accompanying claims, abstract and drawings), or to any novel one, orany novel combination, of the steps of any method or process sodisclosed.

1. Lighting apparatus comprising a light source, the light source beingencapsulated in a protective medium to seal the light source againstingress of moisture, the lighting apparatus including a heat sink, theheat sink having a first region in communication with the light sourceto receive heat from the light source, and a second region whichprojects externally of the protective medium, such that the heat sinkcan dissipate heat to the ambient area.
 2. Lighting apparatus as claimedin claim 1, in which the light source comprises a light emitting diode(LED).
 3. Lighting apparatus as claimed in claim 1, in which the lightsource has a light emitting region adjacent to, and projecting from, theprotective medium.
 4. Lighting apparatus as claimed in claim 1, in whichthe light source has a light emitting region protected by a cover, thecover being sealed to the protective medium and being such that lightmay pass through it.
 5. Lighting apparatus as claimed in claim 4, inwhich the cover is made of glass.
 6. Lighting apparatus as claimed inclaim 4, in which the cover is made of transparent or translucentplastics material.
 7. Lighting apparatus as claimed in claim 4, in whichthe cover comprises acollimating lens.
 8. Lighting apparatus as claimedin claim 1, in which there is more than one light source arranged withinthe protective medium.
 9. Lighting apparatus as claimed in claim 1, inwhich the light source is arranged to transmit light to the ambient areavia a light transmitting conduit such as a light pipe or fibre opticbundle.
 10. Lighting apparatus as claimed in claim 1, in which the heatsink comprises a metal plate.
 11. Lighting apparatus as claimed in claim10, in which the metal is aluminium.
 12. Lighting apparatus as claimedin claim 1, in which the second region of the heat sink serves more thanone purpose.
 13. Lighting apparatus as claimed in claim 12, in which thesecond region carries manufacturer's information or advertising logoinformation.
 14. Lighting apparatus as claimed in claim 12, in which thesecond region is shaped into a bracket, for example to fit into a socketon a standard miner's or caver's helmet.
 15. Lighting apparatus asclaimed in claim, in which the second region is shaped to form a box orother enclosure.
 16. Lighting apparatus as claimed in claim 12, in whichthe second region has a secondary function as part of a car body such asa car wing.